FREELTON, Ont. — Two people were killed in a southern Ontario highway collision on Thursday after a car being chased by police crashed into a transport truck.

The incident in rural Hamilton is being investigated by Ontario's police watchdog.

A car involved was being followed by Waterloo regional police and collided head-on with a transport truck on Highway 6, killing the male driver and a female passenger, said the Special Investigations Unit.

Waterloo regional police Insp. Michael Haffner said the force got a call Thursday morning from a concerned citizen reporting the possible abduction of a woman from Cambridge, Ont.

"The officers did locate the vehicle being driven by a male, with a female passenger, and officers attempted to stop the vehicle. The driver did not stop, and a pursuit was initiated," Haffner said.

"Around 9:55 a.m., the vehicle was involved in a head-on collision with an oncoming transport truck."

The driver of the truck was not injured.

SIU spokeswoman Monica Hudon said the incident began around 9:30 a.m. in Cambridge, when police were "made aware of an assault on a woman."

The suspect vehicle went east on Highway 401 and later turned south onto Highway 6 before colliding with the tractor-trailer, Hudon said.

"At this point in time we can't confirm if it was a pursuit or not," Hudon said, adding that the SIU was describing the police action as a "follow."

"It's quite the tragic collision," she said of the crash that left parts of the mangled vehicle strewn across the highway. "Our investigators are still trying to identify the victims."

The SIU is an arm's-length agency that investigates reports involving police where there has been death, serious injury or allegations of sexual assault.